Self executing and self disposing signal for imperative programming languages

ABSTRACT

DESCRIBED HEREIN ARE SYSTEMS, APPARATUS, METHODS AND COMPUTER PROGRAM PRODUCTS FOR IMPLEMENTING A SELF EXECUTING AND SELF DISPOSING SIGNAL FOR AN IMPERATIVE PROGRAMMING LANGUAGE. THE SELF EXECUTING AND SELF DISPOSING SIGNAL MAY BE UTILIZED BY A REACTIVEX SPECIFICATION PROGRAMMING LANGUAGE. THE SIGNAL MAY BE EXECUTED BEFORE IT IS OBSERVED BY AN EXTERNAL OBSERVER, REDUCING LOAD TIMES. ADDITIONALLY, THE SIGNAL MAY ALLOW FOR MULTIPLE OBSERVERS TO OBSERVE THE OUTPUT OF THE SIGNAL AT THE SAME TIME AND MAY BE SELF DISPOSING TO PREVENT MEMORY LEAKS.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection, The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure as it appears in the United States Patent andTrademark Office patent file or records but otherwise reserves allcopyright rights whatsoever

FIELD OF TECHNOLOGY

This patent document relates generally to data processing and morespecifically to signal processing for imperative programming languagesutilizing the ReactiveX specification.

BACKGROUND

Imperative programming languages that follow the ReactiveX specificationutilize signals that operate on data in a flow based manner instead of astate based manner. Thus, in such languages, an observer dispatches(e.g., initiates) a signal and observes the state of the signal, and thechanges thereof, during execution of the signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The included drawings are for illustrative purposes and serve only toprovide examples of possible structures and operations for the disclosedinventive systems, apparatus, methods and computer program products fora self executing and self disposing signal used in imperativeprogramming. These drawings in no way limit any changes in form anddetail that may be made by one skilled in the art without departing fromthe spirit and scope of the disclosed implementations.

FIG. 1 illustrates an example configuration of a signal function in animperative programming language, configured in accordance with one ormore embodiments.

FIG. 2 illustrates another example configuration of a signal function inan imperative programming language, configured in accordance with one ormore embodiments.

FIG. 3 illustrates an example of a method for imperative programmingsignal processing, performed in accordance with one or more embodiments.

FIG. 4 illustrates another example of a method for imperativeprogramming signal processing, performed in accordance with one or moreembodiments.

FIG. 5 illustrates an example of a computing system, configured inaccordance with one or more embodiments.

FIGS. 6A and 6B illustrate other examples of computing systems,configured in accordance with one or more embodiments.

FIG. 7 illustrates an example of a computing device, configured inaccordance with one or more embodiments.

DETAILED DESCRIPTION

Some implementations of the disclosed systems, apparatus, methods andcomputer program products are configured for implementing aself-executing and self-disposing signal for an imperative programminglanguage. The signal may be utilized by a ReactiveX specificationprogramming language to allow for a signal that is dispatched (e.g.,initiated or started) before it is observed by an external observer,reducing load times. Additionally, the signal allows for multipleobservers to observe the signal at the same time. The signal is alsoself disposing to prevent memory leaks.

In typical ReactiveX specification languages, a signal is onlydispatched when the signal is observed by an observer. Typically, theobserver is an external observer (e.g., an observer associated withanother process) that observes the flow of data of the signal to utilizethe output of the signal for another process. Thus, once the externalobserver begins observing the signal and, thus, dispatches the signal,the external observer then observes the flow (e.g., result ofprocessing) of the signal. In such configurations, a signal is onlydispatched when an external observer observes the signal and, thus,cannot be pre-executed (e.g., to increase execution speed). Furthermore,such signals are generally configured to dispatch a separate processeach time a different observer observes the signal. As such, eachinstance of such signals can only be observed by one observer and,accordingly, observers are unable to share data flow for the samesignal.

Todd is a customer of HighSavings Bank that is using HighSavings' mobileapplication to obtain details about his account. The mobile applicationis programmed on the ReactiveX specification. Todd, in a series ofactions right before his monthly review meeting, commands theapplication to load his account data, load a trading platform to executetrades, and, finally, extrapolate his monthly savings based on theamount he has spent in the month to date. Unfortunately for Todd,HighSavings Bank's application is programmed without self-executingsignals and, thus, the actions for each of his commands begin executingonly after an observer is dispatched to observe the state of thecommands. This leads to a slower load time, resulting in Todd beingunable to view the extrapolation of his monthly savings before hisreview meeting.

By contrast, described herein is a signal, for an imperative programminglanguage that conforms to the ReactiveX specification, configured to bedispatched before external observers are present to observe the signal.By way of example, using the techniques discussed herein, processing ofthe signal may include creating the signal, creating an internalobserver, and dispatching the signal due to the presence of the internalobserver. One or a plurality of external observers (e.g., a conventionalobserver that observes the outputs of the signal function) may observethe internal observer to obtain the outputs of the signal function. Thesignal may be disposed upon a determination that the internal observeris not being observed by any external observers and a determination thatthe signal is not being referenced by the first instruction.

The next month, HighSavings Bank has upgraded their mobile applicationto allow their platform to utilize the signals described herein. Toddonce again finds himself using the HighSavings Bank mobile applicationbefore his monthly review meeting. Again, Todd commands the applicationto load his account data, then load a trading platform to executetrades, and, finally, extrapolate his monthly savings based on theamount he has spent in the month to date. As HighSavings Bank'sapplication has been updated, the account data, trading platform, andextrapolation are now all pre-fetched. Thus, this month, the loadingtimes of HighSavings Bank's mobile application is much reduced and Toddis able to view all of his requests before his review meeting.

FIG. 1 illustrates an example configuration of a signal function in animperative programming language, configured in accordance with one ormore embodiments. FIG. 1 illustrates signal 150. As shown in FIG. 1,signal 150 includes signal function 151. Signal function 151 may be afunction that processes data and provides an output (e.g., a data flowto external observer 160). When signal function 151 is directly observedby external observer 160, memory is allocated to signal function 151.

In imperative programming languages conforming to the ReactiveXspecification, signal function 151 only dispatches upon being observedby an observer. In the embodiment shown in FIG. 1, external observer 160dispatches signal function 151 when external observer 160 observessignal function 151. In such an embodiment, signal function 151 may thusbe declared without being dispatched and remain essentially idle beforeexternal observer 160 observes and, thus, initiates signal function 151.Furthermore, only one observer may directly observe signal function 151and, upon the external observer ceasing to observe signal function 151,signal function 151 is disposed. Thus, signal function 151 caneffectively interface with only one external observer in theconfiguration of FIG. 1.

External observer 160 is associated with another function different fromthat of signal function 151. When observing signal function 151,external observer 160 obtains outputs from operation of signal function151 and provides it to the other function. Additionally, signal function151 provides a “disposable” which external observer 160 retains asdisposable 165. Disposable 165 allows for external observer 160 todispose of (e.g. cancel) the observation when the desired output fromsignal function 151 has been obtained and/or when otherwise desired todispose of signal function 151. Disposable 165 is disposed by externalobserver 160 when external observer 160 no longer requires furtheroutputs from signal function 151 and, accordingly, causes externalobserver 160 to cease observing signal function 151, disposing of signalfunction 151. Once signal function 151 has been disposed of, memoryallocated to operation of signal function 151 is de-allocated.

FIG. 2 illustrates another example configuration of a signal function inan imperative programming language, configured in accordance with one ormore embodiments. FIG. 2 illustrates self-executing signal 200.Self-executing signal 200 is a self-executing and self-disposing signalthat includes signal function 201, internal observer 203, and disposable205. Signal function 201 may be a function of a program executed by acomputing system (e.g., of a desktop, laptop, smartphone, tablet, orother device) through one or more processors and memories. Code 215 maybe program code that provides instructions for various aspects of acomputer program, such as the creation and operation of variousfunctions, observers, and other aspects of the computer program.

Signal function 201 may be a signal function as described herein. Thus,signal function 201 may be a function that processes data and provides aflow output based on the processing. Outputs from signal function 201may be utilized by other functions. In certain embodiments (e.g., withinReactiveX specifications) signal function 201 may be dispatched (e.g.,initiated) upon being observed by an observer. In the embodimentsdescribed herein, in order to dispatch signal function 201 before anyexternal observers are observing signal function 201, internal observer203 is created. In certain embodiments, internal observer 203 is createdat the same time as signal function 201. In such an embodiment, signalfunction 201 may be dispatched at the time of creation or shortlythereafter. In other embodiments, code 215 may create the internalobserver during a time later than the time of creation of signalfunction 201. In such an embodiment, code 215 may thus control whensignal function 201 will be dispatched through timing of the creation ofinternal observer 203.

Thus, referring back to the example of Todd and HighSavings Bank,HighSavings Bank's updated application may create a first signal and asecond signal when Todd loads the portion of the application thatincludes the trading platform. The first signal may recall the currentvalue of all of Todd's holdings. As such, the first signal is createdwith an internal observer to immediately initiate the first signal uponloading of the portion of the application. The second signal may obtaina quote of the current value of a stock that the user is interested inpurchasing. In order to decrease load times, the second signal may alsobe created at the time of loading of the portion of the application.However, as equity values are constantly changing, the internal observerof the second signal function is not created until the user (Todd)enters a stock signal that he is interested in a quotation for.

Internal observer 203 is an observer of self-executing signal 200 and,unlike external observers 207, 209, and 211, not an observer belongingto another external function. Internal observer 203 may be configured tobe observed by a plurality of external observers. In the embodiment ofFIG. 2, external observers 207, 209, and 211 may all observe internalobserver 203. Internal observer 203 may obtain the outputs (e.g.,results) of signal function 201 when signal function 201 is run. Byobserving internal observer 203, each of the external observers may alsoobtain the output from signal function 201 (e.g., internal observer 203provides the outputs of signal function 201 to each of externalobservers 207, 209, and 211). Thus, a plurality of external observersmay each obtain the output of signal function 201 despite, in certainembodiments, signal function 201 being configured to only be observed byone observer.

Furthermore, the external observers are able to observe internalobserver 203 at a time after the creation of internal observer 203,allowing for signal function 201 to be dispatched before being observedby any external observers. Additionally, the external observers are freeto observe and disengage from internal observer 203 without thedisengagement of the external observer leading to the disposing ofsignal function 201. As such, signal function 201 will continue toexecute regardless of whether any external observers are observinginternal observer 203.

Continued operation of self-executing signal 200 by the electronicdevice consumes resources and/or memory of the electronic device. Thus,self-executing signal 200 includes disposable 205. Disposable 205 is aportion of self-executing signal 200 and determines when it isappropriate to dispose of self-executing signal 200. When disposable 205is disposed, signal function 201 is disposed (e.g., canceled).Disposable 205 may reference internal observer 203 and/or code 215 todetermine whether to dispose of self-executing signal 200.

Disposable 205 may determine if code 215 references self-executingsignal 200. If code 215 references self-executing signal 200 adetermination may be made that self-executing function 200 and/or signalfunction 201 is still needed and, as such, should not be disposed. Ifdisposable 205 determines that no external observers are observinginternal observer 203 and code 215 is not referencing self-executingsignal 200, then disposable 205 may determine that self-executingfunction 200 and/or signal function 201 is no longer needed and, thus,dispose of self--executing function 200 and/or signal function 201.

Furthermore, in certain embodiments, disposable 205 may also beconfigured to determine whether any external observers are observinginternal observer 203. If there is any external observer observinginternal observer 203, disposable 205 may not dispose of self-executingsignal 200 and/or signal function 201.

In certain embodiments, disposable 205 may dispose of self-executingsignal 200 and/or signal function 201 upon instructions from code 215.Thus, unlike typical techniques that dispose of signals with adisposable of the external observer and lacks the ability for signals tobe disposed while being observed by the external observer, the currenttechniques allow for code 215 to provide an explicit command todisposable 205 to dispose of self-executing signal 200 and/or signalfunction 20:1. Upon receiving the explicit command, disposable 205 mayproceed to dispose of self--executing signal 200 and/or signal function201 regardless of whether any external observers are observing internalobserver 203. In certain other embodiments, upon receiving the explicitcommand, disposable 205 may determine if any external observers areobserving internal observer 203 and, if no external observers areobserving internal observer 203, dispose of self-executing signal 200and/or signal function 201.

FIG. 3 illustrates an example of a method for imperative programmingsignal processing, performed in accordance with one or more embodiments.FIG. 3 illustrates imperative programming signal processing technique300 that creates, operates, and disposes of a self-executing signal asdescribed herein. The self-executing signal may be a portion of aprogram and may be controlled by program code.

In step 302, a self-executing signal that includes a signal function iscreated. The self-executing signal may include a signal function asdescribed herein (e.g., signal function 201). The self-executing signalcan also include an internal observer and a disposable in certainembodiments.

In step 304, the signal function is dispatched (e.g., executed). Thesignal function may be configured to perform one or more operations. Invarious embodiments, the signal function may be dispatched upon beingobserved by an internal observer. In the embodiment described in FIG. 3,the internal observer is created along with the signal function (in step302). Other embodiments, such as the embodiment described in FIG. 3, maycreate the internal observer at a time later than that of the time whenthe signal function is created, as described herein. The self-executingsignal, upon determining that the signal function is observed by theinternal observer, dispatches the signal function.

In various embodiments, the outputs are a data flow from execution ofthe signal function. The internal observer observes the execution of thesignal function arid obtains the outputs. As described herein, due tothe presence of the internal observer, the signal function may beginexecuting before any external observers are observing the internalobserver. Such a technique allows for pre-executing of the signalfunction, reducing load times. Thus, for example, a signal function maybegin executing before its output is needed. In such an embodiment,external observers are not required to observe the internal observer(e.g., to dispatch the signal function) before the external observerrequires the output. External observers can then observe the internalobserver to obtain the output when the external observer requires theoutput.

During execution of the signal function, external observers may observethe internal observer to obtain, from observing the internal observer,outputs from the execution of the signal function. In variousembodiments, the external observer observing the internal observer mayobtain outputs from the signal function that the signal function isproviding at that time. As the signal function provides data in a flowbased manner, the external observer thus obtains outputs from the signalfunction of the flow at the times when the external observer isobserving the internal observer.

In various embodiments, the internal observer may include a buffer. Thebuffer may be configured to store a number of the last events outputfrom the signal function. The number may be set as needed (e.g.,programmed to store the last 1-10 or more events, as needed). The bufferallows the internal observer to store and replay the number of previousevents, allowing external observers to observe those events. As such, anexternal observer that views the internal observer may be able to replaythe previous events and obtain the data regardless of whether theexternal observer had been observing the internal observer when theevents were performed.

In step 306, the disposable determines if the self-executing signal isreferenced by any other portions of the code. Thus, for example, thedisposable may determine if the self-executing signal is beingreferenced by code currently being executed by the program and/or codethat the program may execute (e.g., by utilizing reference countingbehavior or through another technique). If the self-executing signal isreferenced by any part of those portions of the code, the disposable maydetermine that the self-executing signal should still be executed and,thus, the technique returns to step 304 and continues executing thesignal function. If the disposable determines that no portions of thecode (either being executed or remaining) references the self-executingsignal, the technique may proceed to step 308. In various embodiments,step 306 may be periodically performed (e.g., at regular timeintervals), performed according to milestones (e.g., when execution ofthe signal function has accomplished various tasks or has finishedexecuting), or according to other conditions.

In step 308, after determining that the self-executing signal is notbeing referenced by any other portions of code, the self-executingfunction may determine if the function should be disposed of. Disposingof the signal conserves processing and memory resources and preventsmemory leaks. In step 308, the disposable determines if any externalobservers are observing the internal observer. If the disposabledetermines that the internal observer is being observed by one or moreexternal observers, the technique returns to step 304 and continuesexecuting the signal function. If the disposable determines that theinternal observer is not being observed by any external observers, thetechnique may proceed to step 310.

In step 310, the disposable may dispose of the signal function and/orthe self-executing signal, as described herein. Thus, the disposable maycease executing the signal function and/or the self-executing signal andfree up system resources. The technique is then finished in step 312.

Returning to the example of HighSavings Bank, upon entering his meeting,Todd leaves HighSavings Bank's application open on his phone. Todd hadpreviously queried a stock quote for AlwaysUp and had purchased 200shares of AlwaysUp based on the quote. Todd had also requested that theapplication extrapolate his monthly savings based on his currentspending.

HighSavings' application, upon determining that the stock quote has beenprovided, checks to see if it should dispose of the quoting signal. Thequoting function utilizes a pre-executing quotation signal, as describedherein, to more quickly obtain the quote. An external observerassociated with the stock purchasing function of the applicationobserves the internal observer of the pre-executing quotation signal, toobtain up to date quotes. The pre-executing quotation signal, after Toddhas purchased his stock, determines that no external observer isobserving the internal observer of the pre-executing quotation signal.It also determines that no other portions of the code references thepre-executing quotation signal as no other portion of the code requiresa stock quote for AlwaysUp. The disposable then determines that thepre-executing quotation signal can be disposed of and accordinglydisposes of the pre-executing quotation signal.

HighSavings' application also uses a pre-executing forecasting signalfor extrapolating the monthly savings. The application also checks tosee if the extrapolation signal should be disposed. A disposable of thepre-executing forecasting signal then determines that no currentexternal observers are observing the internal observer of thepre-executing forecasting signal. However, the disposable determinesthat the extrapolation auto updates based on new data and that thepre-executing forecasting signal is referenced by code for the autoupdates. Thus, the application determines that the pre-executingforecasting signal should not be disposed.

FIG. 4 illustrates another example of a method for imperativeprogramming signal processing, performed in accordance with one or moreembodiments. FIG. 4 describes a technique of creating and processing aself-executing signal that includes a signal function. The techniquedescribed in FIG. 4 includes similar steps to that of FIG. 3. Forexample, steps 402, 408, 410, and 412 are similar to steps 302, 304,306, and 308 of FIG. 3, respectively. Thus, in step 402, theself-executing function is created. The self-executing signal includes asignal function and the signal function may be created at step 402 alongwith the self-executing signal.

In step 404, the internal observer is created. In step 404, the internalobserver is created at a time later than the time that the signalfunction is created (in step 402). As such, the program code maydispatch the signal function at a time later than the creation of thesignal, but before any external observers observe the internal observer,by controlling when the internal observer is created. After the internalobserver has been created, the internal observer then observes thesignal function in step 406. Accordingly, in step 408, theself-executing signal, upon determining that the signal function isobserved by the internal observer, executes the signal function.

Upon or during execution of the signal function, the self-executingsignal determines if the signal function and/or the self-executingfunction should be disposed, through steps 410 and 412. Steps 410 and412 are similar to steps 306 and 308 of FIG. 3, respectively. Thedetermination of whether to dispose of the signal function and/orself-executing function, made in steps 410 and 412, and thus be similarto the determination technique described for steps 306 and 308.

If the disposable determines that the signal function and/or theself-executing function should be disposed, the disposable may disposeof the signal function and/or the self-executing function in step 414.Thus, the disposable may cease executing the signal function and/or theself-executing function and memory allocated to the self-executingsignal may be de-allocated and freed to be used by other processes. Thetechnique is then finished in step 416.

FIG. 5 illustrates an example of a computing system, configured inaccordance with one or more embodiments. FIG. 5 shows a block diagram ofan example of an environment 510 that includes an on-demand databaseservice configured in accordance with some implementations. Environment5:10 may include user systems 512, network 514, database system 516,processor system 517, application platform 518, network interface 520,tenant data storage 522, tenant data 523, system data storage 524,system data 525, program code 526, process space 528, User Interface(UI) 530, Application Program Interface (API) 532, PL/SOQL 534, saveroutines 536, application setup mechanism 538, application servers 550-1through 550-N, system process space 552, tenant process spaces 554,tenant management process space 560, tenant storage space 562, userstorage 564, and application metadata 566. Some of such devices may beimplemented using hardware or a combination of hardware and software andmay be implemented on the same physical device or on different devices.Thus, terms such as “data processing apparatus,” “machine,” “server” and“device” as used herein are not limited to a single hardware device, butrather include any hardware and software configured to provide thedescribed functionality.

An on-demand database service, implemented using system 516, may bemanaged by a database service provider. Some services may storeinformation from one or more tenants into tables of a common databaseimage to form a multi-tenant database system (MTS). As used herein, eachMIS could include one or more logically and/or physically connectedservers distributed locally or across one or more geographic locations.Databases described herein may be implemented as single databases,distributed databases, collections of distributed databases, or anyother suitable database system. A database image may include one or moredatabase objects. A relational database management system (RDBMS) or asimilar system may execute storage and retrieval of information againstthese objects.

In some implementations, the application platform 18 may be a frameworkthat allows the creation, management, and execution of applications insystem 516. Such applications may be developed by the database serviceprovider or by users or third-party application developers accessing theservice. Application platform 518 includes an application setupmechanism 538 that supports application developers' creation andmanagement of applications, which may be saved as metadata into tenantdata storage 522 by save routines 536 for execution by subscribers asone or more tenant process spaces 554 managed by tenant managementprocess 560 for example, Invocations to such applications may be codedusing PL/SOQL 534 that provides a programming language style interfaceextension to API 532. A detailed description of some PL/SOQL languageimplementations is discussed in commonly assigned U.S. Pat. No.7,730,478, titled METHOD AND SYSTEM FOR ALLOWING ACCESS TO DEVELOPEDAPPLICATIONS VIA A MULTI-TENANT ON-DEMAND DATABASE SERVICE, by CraigWeissman, issued on Jun. 1, 2010, and hereby incorporated by referencein its entirety and for all purposes. Invocations to applications may bedetected by one or more system processes. Such system processes maymanage retrieval of application metadata 566 for a subscriber makingsuch an invocation, Such system processes may also manage execution ofapplication metadata 566 as an application in a virtual machine.

In some implementations, each application server 550 may handle requestsfor any user associated with any organization. A load balancing function(e.g., an F5 Big-IP load balancer) may distribute requests to theapplication servers 550 based on an algorithm such as least-connections,round robin, observed response time, etc. Each application server 550may be configured to communicate with tenant data storage 522 and thetenant data 523 therein, and system data storage 524 and the system data525 therein to serve requests of user systems 512. The tenant data 523may be divided into individual tenant storage spaces 562, which can beeither a physical arrangement and/or a logical arrangement of data.Within each tenant storage space 562, user storage 564 and applicationmetadata 566 may be similarly allocated for each user. For example, acopy of a user's most recently used (MRU) items might be stored to userstorage 564. Similarly, a copy of MRU items for an entire tenantorganization may be stored to tenant storage space 562. A UI 530provides a user interface and an API 532 provides an applicationprogramming interface to system 516 resident processes to users and/ordevelopers at user systems 512.

System 516 may implement a web-based system that utilizes imperativeprogramming with self-executing signals. For example, in someimplementations, system 516 may include application servers configuredto implement and execute software applications based on imperativeprogramming formats such as ReactiveX that contains self-executingfunctions. The application servers may be configured to provide relateddata, code, forms, web pages and other information to and from usersystems 512. Additionally, the application servers may be configured tostore information to, and retrieve information from a database system.Such information may include related data, objects, and/or Webpagecontent. With a multi-tenant system, data for multiple tenants may bestored in the same physical database object in tenant data storage 522,however, tenant data may be arranged in the storage medium(s) of tenantdata storage 522 so that data of one tenant is kept logically separatefrom that of other tenants. In such a scheme, one tenant may not accessanother tenant's data, unless such data is expressly shared.

Several elements in the system shown in FIG. 5 include conventional,well-known elements that are explained only briefly here. For example,user system 512 may include processor system 512A, memory system 512B,input system 512C, and output system 5 12D. A user system 512 may beimplemented as any computing device(s) or other data processingapparatus such as a mobile phone, laptop computer, tablet, desktopcomputer, or network of computing devices. User system 12 may run anInternet browser allowing a user (e.g., a subscriber of an MTS) of usersystem 512 to access, process and view information, pages andapplications available from system 516 over network 514. Network 514 maybe any network or combination of networks of devices that communicatewith one another, such as any one or any combination of a LAN (localarea network), WAN (wide area network), wireless network, or otherappropriate configuration.

The users of user systems 512 may differ in their respective capacities,and the capacity of a particular user system 512 to access informationmay be determined at least in part by “permissions” of the particularuser system 512. As discussed herein, permissions generally governaccess to computing resources such as data objects, components, andother entities of a computing system. “Permission sets” generally referto groups of permissions that may be assigned to users of such acomputing environment. For instance, the assignments of users andpermission sets may be stored in one or more databases of System 516.Thus, users may receive permission to access certain resources. Apermission server in an on-demand database service environment can storecriteria data regarding the types of users and permission sets to assignto each other. For example, a computing device can provide to the serverdata indicating an attribute of a user (e.g., geographic location,industry, role, level of experience, etc.) and particular permissions tobe assigned to the users fitting the attributes. Permission sets meetingthe criteria may be selected and assigned to the users. Moreover,permissions may appear in multiple permission sets. In this way, theusers can gain access to the components of a system.

In some an on-demand database service environments, an ApplicationProgramming Interface (API) may be configured to expose a collection ofpermissions and their assignments to users through appropriatenetwork-based services and architectures, for instance, using SimpleObject Access Protocol (SOAP) Web Service and Representational StateTransfer (REST) APIs.

In some implementations, a permission set may be presented to anadministrator as a container of permissions. However, each permission insuch a permission set may reside in a separate API object exposed in ashared API that has a child-parent relationship with the same permissionset object. This allows a given permission set to scale to millions ofpermissions for a user while allowing a developer to take advantage ofjoins across the API objects to query, insert, update, and delete anypermission across the millions of possible choices. This makes the APIhighly scalable, reliable, and efficient for developers to use.

In some implementations, a permission set API constructed using thetechniques disclosed herein can provide scalable, reliable, andefficient mechanisms for a developer to create tools that manage auser's permissions across various sets of access controls and acrosstypes of users. Administrators who use this tooling can effectivelyreduce their time managing a user's rights, integrate with externalsystems, and report on rights for auditing and troubleshooting purposes.By way of example, different users may have different capabilities withregard to accessing and modifying application and database information,depending on a user's security or permission level, also calledauthorization. In systems with a hierarchical role model, users at onepermission level may have access to applications, data, and databaseinformation accessible by a lower permission level user, but may nothave access to certain applications, database information, and dataaccessible by a user at a higher permission level.

As discussed above, system 516 may provide on-demand database service touser systems 512 using an MIS arrangement. By way of example, one tenantorganization may be a company that employs a sales force where eachsalesperson uses system 516 to manage their sales process. Thus, a userin such an organization may maintain contact data, leads data, customerfollow-up data, performance data, goals and progress data, etc., allapplicable to that user's personal sales process (e.g., in tenant datastorage 522). In this arrangement, a user may manage his or her salesefforts and cycles from a variety of devices, since relevant data andapplications to interact with (e.g., access, view, modify, report,transmit, calculate, etc.) such data may be maintained and accessed byany user system 512 having network access.

When implemented in an MIS arrangement, system 516 may separate andshare data between users and at the organization-level in a variety ofmanners. For example, for certain types of data each user's data mightbe separate from other users' data regardless of the organizationemploying such users. Other data may be organization-wide data, which isshared or accessible by several users or potentially all users form agiven tenant organization. Thus, some data structures managed by system516 may be allocated at the tenant level while other data structuresmight be managed at the user level. Because an MIS might supportmultiple tenants including possible competitors, the MTS may havesecurity protocols that keep data, applications, and application useseparate. In addition to user-specific data and tenant-specific data,system 516 may also maintain system-level data usable by multipletenants or other data. Such system-level data may include industryreports, news, postings, and the like that are sharable between tenantorganizations.

In some implementations, user systems 512 may be client systemscommunicating with application servers 550 to request and updatesystem-level and tenant-level data from system 516. By way of example,user systems 512 may send one or more queries requesting data of adatabase maintained in tenant data storage 522 and/or system datastorage 524. An application server 550 of system 516 may automaticallygenerate one or more SQL statements (e.g., one or more SQL queries) thatare designed to access the requested data. System data storage 524 maygenerate query plans to access the requested data from the database.

The database systems described herein may be used for a variety ofdatabase applications. By way of example, each database can generally beviewed as a collection of objects, such as a set of logical tables,containing data fitted into predefined categories. A “table” is onerepresentation of a data object, and may be used herein to simplify theconceptual description of objects and custom objects according to someimplementations. It should be understood that “table” and “object” maybe used interchangeably herein. Each table generally contains one ormore data categories logically arranged as columns or fields in aviewable schema. Each row or record of a table contains an instance ofdata for each category defined by the fields. For example, a CRMdatabase may include a table that describes a customer with fields forbasic contact information such as name, address, phone number, faxnumber, etc. Another table might describe a purchase order, includingfields for information such as customer, product, sale price, date, etc.In some multi-tenant database systems, standard entity tables might beprovided for use by all tenants. For CRM database applications, suchstandard entities might include tables for case, account, contact, lead,and opportunity data objects, each containing pre-defined fields. Itshould be understood that the word “entity” may also be usedinterchangeably herein with “object” and “table”.

In some implementations, tenants may be allowed to create and storecustom objects, or they may be allowed to customize standard entities orobjects, for example by creating custom fields for standard objects,including custom index fields. Commonly assigned U.S. Pat. No.7,779,039, titled CUSTOM ENTITIES AND FIELDS IN A MULTI-TENANT DATABASESYSTEM, by Weissman et al., issued on Aug. 17, 2010, and herebyincorporated by reference in its entirety and for all purposes, teachessystems and methods for creating custom objects as well as customizingstandard objects in an MTS. In certain implementations, for example, allcustom entity data rows may be stored in a single multi-tenant physicaltable, which may contain multiple logical tables per organization. Itmay be transparent to customers that their multiple “tables” are in factstored in one large table or that their data may be stored in the sametable as the data of other customers.

FIGS. 6A and 6B illustrate other examples of computing systems,configured in accordance with one or more embodiments. FIG. 6A shows asystem diagram of an example of architectural components of an on-demanddatabase service environment 600, configured in accordance with someimplementations. A client machine located in the cloud 604 maycommunicate with the on-demand database service environment via one ormore edge routers 608 and 612. A client machine may include any of theexamples of user systems 512 described above. The edge routers 608 and612 may communicate with one or more core switches 620 and 624 viafirewall 616. The core switches may communicate with a load balancer628, which may distribute server load over different pods, such as thepods 640 and 644 by communication via pod switches 632 and 636. The pods640 and 644, which may each include one or more servers and/or othercomputing resources, may perform data processing and other operationsused to provide on-demand services. Components of the environment maycommunicate with a database storage 656 via a database firewall 648 anda database switch 652.

Accessing an on-demand database service environment may involvecommunications transmitted among a variety of different components. Theenvironment 600 is a simplified representation of an actual on-demanddatabase service environment. For example, some implementations of anon-demand database service environment may include anywhere from one tomany devices of each type. Additionally, an on-demand database serviceenvironment need not include each device shown, or may includeadditional devices not shown, in FIGS. 6A and 6B.

The cloud 604 refers to any suitable data network or combination of datanetworks, which may include the Internet. Client machines located in thecloud 604 may communicate with the on-demand database serviceenvironment 600 to access services provided by the on-demand databaseservice environment 600. By way of example, client machines may accessthe on-demand database service environment 600 to retrieve, store, edit,and/or process information.

In some implementations, the edge routers 608 and 612 route packetsbetween the cloud 604 and other components of the on-demand databaseservice environment 600. The edge routers 608 and 612 may employ theBorder Gateway Protocol (BGP). The edge routers 608 and 612 may maintaina table of IP networks or ‘prefixes’, which designate networkreachability among autonomous systems on the Internet,

In one or more implementations, the firewall 616 may protect the innercomponents of the environment 600 from internet traffic. The firewall616 may block, permit, or deny access to the inner components of theon-demand database service environment 600 based upon a set of rulesand/or other criteria. The firewall 616 may act as one or more of apacket filter, an application gateway, a stateful filter, a proxyserver, or any other type of firewall.

In some implementations, the core switches 620 and 624 may behigh-capacity switches that transfer packets within the environment 600.The core switches 620 and 624 may be configured as network bridges thatquickly route data between different components within the on-demanddatabase service environment. The use of two or more core switches 620and 624 may provide redundancy and/or reduced latency.

In some implementations, communication between the pods 640 and 644 maybe conducted via the pod switches 632 and 636. The pod switches 632 and636 may facilitate communication between the pods 640 and 644 and clientmachines, for example via core switches 620 and 624. Also oralternatively, the pod switches 632 and 636 may facilitate communicationbetween the pods 640 and 644 and the database storage 656. The loadbalancer 628 may distribute workload between the pods, which may assistin improving the use of resources, increasing throughput, reducingresponse times, and/or reducing overhead. The load balancer 628 mayinclude multilayer switches to analyze and forward traffic.

In some implementations, access to the database storage 656 may beguarded by a database firewall 648, which may act as a computerapplication firewall operating at the database application layer of aprotocol stack. The database firewall 648 may protect the databasestorage 656 from application attacks such as structure query language(SQL) injection, database rootkits, and unauthorized informationdisclosure. The database firewall 648 may include a host using one ormore forms of reverse proxy services to proxy traffic before passing itto a gateway router and/or may inspect the contents of database trafficand block certain content or database requests. The database firewall648 may work on the SQL application level atop the TCP/IP stack,managing applications' connection to the database or SQL managementinterfaces as well as intercepting and enforcing packets traveling to orfrom a database network or application interface.

In some implementations, the database storage 656 may be an on-demanddatabase system shared by many different organizations. The on-demanddatabase service may employ a single-tenant approach, a multi-tenantapproach, a virtualized approach, or any other type of databaseapproach. Communication with the database storage 656 may be conductedvia the database switch 652. The database storage 656 may includevarious software components for handling database queries. Accordingly,the database switch 652 may direct database queries transmitted by othercomponents of the environment (e.g., the pods 640 and 644) to thecorrect components within the database storage 656.

FIG. 6B shows a system diagram further illustrating an example ofarchitectural components of an on-demand database service environment,in accordance with some implementations. The pod 644 may be used torender services to user(s) of the on-demand database service environment600. The pod 644 may include one or more content batch servers 664,content search servers 668, query servers 682, file servers 686, accesscontrol system (ACS) servers 680, batch servers 684, and app servers688. Also, the pod 644 may include database instances 690, quick filesystems (QFS) 692, and indexers 694. Some or all communication betweenthe servers in the pod 644 may be transmitted via the switch 636.

In some implementations, the app servers 688 may include a frameworkdedicated to the execution of procedures (e.g., programs, routines,scripts) for supporting the construction of applications provided by theon-demand database service environment 600 via the pod 644. One or moreinstances of the app server 688 may be configured to execute all or aportion of the operations of the services described herein.

In some implementations, as discussed above, the pod 644 may include oneor more database instances 690. A database instance 690 may beconfigured as an MTS in which different organizations share access tothe same database, using the techniques described above. Databaseinformation may be transmitted to the indexer 694, which may provide anindex of information available in the database 690 to file servers 686.The QFS 692 or other suitable filesystem may serve as a rapid-accessfile system for storing and accessing information available within thepod 644. The QFS 692 may support volume management capabilities,allowing many disks to be grouped together into a file system. The QFS692 may communicate with the database instances 690, content searchservers 668 and/or indexers 694 to identify, retrieve, move, and/orupdate data stored in the network file systems (NFS) 696 and/or otherstorage systems.

In some implementations, one or more query servers 682 may communicatewith the NFS 696 to retrieve and/or update information stored outside ofthe pod 644. The NFS 696 may allow servers located in the pod 644 toaccess information over a network in a manner similar to how localstorage is accessed. Queries from the query servers 622 may betransmitted to the NFS 696 via the load balancer 628, which maydistribute resource requests over various resources available in theon-demand database service environment 600. The NFS 696 may alsocommunicate with the QFS 692 to update the information stored on the NFS696 and/or to provide information to the QFS 692 for use by serverslocated within the pod 644.

In some implementations, the content batch servers 664 may handlerequests internal to the pod 644. These requests may be long-runningand/or not tied to a particular customer, such as requests related tolog mining, cleanup work, and maintenance tasks. The content searchservers 668 may provide query and indexer functions such as functionsallowing users to search through content stored in the on-demanddatabase service environment 600. The file servers 686 may managerequests for information stored in the file storage 698, which may storeinformation such as documents, images, basic large objects (BLOBs), etc.The query servers 682 may be used to retrieve information from one ormore file systems. For example, the query system 682 may receiverequests for information from the app servers 688 and then transmitinformation queries to the NFS 696 located outside the pod 644. The ACSservers 680 may control access to data, hardware resources, or softwareresources called upon to render services provided by the pod 644. Thebatch servers 684 may process batch jobs, which are used to run tasks atspecified times. Thus, the batch servers 684 may transmit instructionsto other servers, such as the app servers 688, to trigger the batchjobs.

While some of the disclosed implementations may be described withreference to a system having an application server providing a front endfor an on-demand database service capable of supporting multipletenants, the disclosed implementations are not limited to multi-tenantdatabases nor deployment on application servers. Some implementationsmay be practiced using various database architectures such as ORACLES,DB2® by IBM and the like without departing from the scope of presentdisclosure.

FIG. 7 illustrates an example of a computing device, configured inaccordance with one or more embodiments. FIG. 7 illustrates one exampleof a computing device. According to various embodiments, a system 700suitable for implementing embodiments described herein includes aprocessor 701, a memory module 703, a storage device 705, an interface711, and a bus 715 (e.g., a PCI bus or other interconnection fabric.)System 700 may operate as variety of devices such as an applicationserver, a database server, or any other device or service describedherein. Although a particular configuration is described, a variety ofalternative configurations are possible. The processor 701 may performoperations such as those described herein. Instructions for performingsuch operations may be embodied in the memory 703, on one or morenon-transitory computer readable media, or on some other storage device.Various specially configured devices can also be used in place of or inaddition to the processor 701. The interface 711 may be configured tosend and receive data packets over a network. Examples of supportedinterfaces include, but are not limited to: Ethernet, fast Ethernet,Gigabit Ethernet, frame relay, cable, digital subscriber line (DSL),token ring, Asynchronous Transfer Mode (ATM), High-Speed SerialInterface (HSSI), and Fiber Distributed Data Interface (FDDI). Theseinterfaces may include ports appropriate for communication with theappropriate media. They may also include an independent processor and/orvolatile RAM. A computer system or computing device may include orcommunicate with a monitor, printer, or other suitable display forproviding any of the results mentioned herein to a user.

Any of the disclosed implementations may be embodied in various types ofhardware, software, firmware, computer readable media, and combinationsthereof. For example, some techniques disclosed herein may beimplemented, at least in part, by computer-readable media that includeprogram instructions, state information, etc., for configuring acomputing system to perform various services and operations describedherein. Examples of program instructions include both machine code, suchas produced by a compiler, and higher-level code that may be executedvia an interpreter. Instructions may be embodied in any suitablelanguage such as, for example, Apex, Java, Python, C++, C, HTML, anyother markup language, JavaScript, ActiveX, VBScript, or Perl. Examplesof computer-readable media include, but are not limited to: magneticmedia such as hard disks and magnetic tape; optical media such as flashmemory, compact disk (CD) or digital versatile disk (DVD);magneto-optical media; and other hardware devices such as read-onlymemory (“ROM”) devices and random-access memory (“RAM”) devices, Acomputer-readable medium may be any combination of such storage devices.

In the foregoing specification, various techniques and mechanisms mayhave been described in singular form for clarity. However, it should benoted that some embodiments include multiple iterations of a techniqueor multiple instantiations of a mechanism unless otherwise noted. Forexample, a system uses a processor in a variety of contexts but can usemultiple processors while remaining within the scope of the presentdisclosure unless otherwise noted. Similarly, various techniques andmechanisms may have been described as including a connection between twoentities. However, a connection does not necessarily mean a direct,unimpeded connection, as a variety of other entities (e.g., bridges,controllers, gateways, etc.) may reside between the two entities.

In the foregoing specification, reference was made in detail to specificembodiments including one or more of the best modes contemplated by theinventors. While various implementations have been described herein, itshould be understood that they have been presented by way of exampleonly, and not limitation. For example, some techniques and mechanismsare described herein in the context of on-demand computing environmentsthat include MTSs. However, the techniques of disclosed herein apply toa wide variety of computing environments, Particular embodiments may beimplemented without some or all of the specific details describedherein. In other instances, well known process operations have not beendescribed in detail in order to avoid unnecessarily obscuring thedisclosed techniques. Accordingly, the breadth and scope of the presentapplication should not be limited by any of the implementationsdescribed herein, but should be defined only in accordance with theclaims and their equivalents.

1. A method for processing a signal using imperative programming, themethod comprising: creating, based on a first indication within a firstcode, a signal; determining that the signal is observed by an internalobserver; begin processing of the signal based on the determining thatthe signal is observed by the internal observer; determining, after thebeginning processing of the signal, that the signal is not beingreferenced by the first code; determining, after the determining thatthe signal is not being referenced by the first code, that the internalobserver is not being observed by any external observers; and disposingthe signal based on the determining that the internal observer is notbeing observed by any external observers and the determining that thesignal is not being referenced by the first code.
 2. The method of claim1, further comprising: creating the internal observer.
 3. The method ofclaim 2, wherein the internal observer is created along with the signal,and wherein the internal observer observes the signal after the creatingof the internal observer.
 4. The method of claim 2, further comprising:observing, by a plurality of external observers, the internal observerto allow the plurality of external observers to each receive outputsfrom the signal.
 5. The method of claim 4, wherein the beginning theprocessing of the signal is at a first time, wherein the observing, by aplurality of external observers, the internal observer is at a secondtime, and wherein the first time is before the second time.
 6. Themethod of claim 4, further comprising: determining, after the beginningprocessing of the signal, that the internal observer is observed by oneor more external observers.
 7. The method of claim 1, wherein the signalis a ReactiveX specification signal,
 8. The method of claim 1, furthercomprising: deallocating the signal from memory after disposing of thesignal.
 9. A computer program product comprising computer-readableprogram code capable of being executed by one or more processors whenretrieved from a non-transitory computer-readable medium, the programcode comprising instructions configurable to cause operationscomprising: creating a signal comprising a disposable; determining thatthe signal is observed by an internal observer; begin processing of thesignal based on the determining that the signal is observed by theinternal observer; determining, with the disposable, that conditions fordisposing of the signal have been met; and disposing the signal.
 10. Thecomputer program product of claim 9, wherein the conditions comprise:that the signal is no longer referenced by the program code; and thatthe internal observer is not being observed by any external observers.11. The computer program product of claim 9, wherein the operationsfurther comprise: creating the internal observer.
 12. The computerprogram product of claim 11, wherein the internal observer is createdalong with the signal, and wherein the internal observer observes thesignal after the creating of the internal observer.
 13. The computerprogram product of claim 11, wherein the operations further comprise:receiving, by the internal observer, an output from the processing ofthe signal based on the internal observer observing the signal.
 14. Thecomputer program product of claim 13, wherein the operations furthercomprise: observing, by a plurality of external observers, the internalobserver to allow the plurality of external observers to each receiveoutputs from the signal.
 15. The computer program product of claim 14,wherein the beginning the processing of the signal is before anyexternal observers are observing the internal observer.
 16. The computerprogram product of claim 9, wherein the conditions comprise: receivingan instruction to cease operation of the signal.
 17. A computing systemimplemented using a server system, the computer system configurable tocause execution of a pre-executing signal, the pre-executing signalcomprising: a signal function, configured to begin processing whenobserved by an observer and return an output based on the processing; aninternal observer, configured to observe the signal function to beginthe processing of the signal function and receive the output from theprocessing of the signal function, wherein the internal observer isconfigured to be observed by a plurality of external observers to allowthe plurality of external observers to each view the output from theprocessing of the signal function; and a disposable, configured to:determine that the signal is not being referenced by program code;determine that the internal observer is not being observed by anyexternal observers; and cause, based on the determining that the signalis not being referenced by the program code and by any externalobservers, disposal of the signal.
 18. The computing system of claim 17,further comprising: one or more external observers.
 19. The computingsystem of claim 17, wherein the internal observer comprises a bufferconfigured to store a pre-determined number of outputs and configured toallow the plurality of external observers to view the number of outputs.20. The computing system of claim 17, wherein the signal function is aReactiveX specification signal function.